Garelick, who was with the FAA for 43 yearsand spent the final 18 as an accident investigator, said that even though the crash scene has been compromised, there are clues untrained people would not recognize.

"The evidence is still there," Garelick said. "You can't completely destroy the evidence and the teams that are going in there – they're very good at what they do."

President Barack Obama confirmed Friday that at least one American was aboard the Malaysian Airlines jetliner that crashed in Ukraine after being shot down Thursday morning.